1. Field of the Invention
The present invention relates to field emission devices and, more particularly, to a pixel tube for a field emission device.
2. Description of Related Art
Field emission devices are based on emission of electrons in a vacuum. Electrons are emitted from micron-sized tips in a strong electric field, and the electrons are accelerated and collide with a fluorescent material. The fluorescent material then emits visible light. Field emission devices are thin, light weight, and provide high levels of brightness.
Conventionally, a material of the tips is selected from the group consisting of molybdenum (Mo) and silicon (Si). With the development of nano-technology, carbon nanotubes (CNTs) are also used for the tips of the field emission devices.
Theoretically, CNTs have small diameters and large slenderness (i.e. diameter/length) ratios thus making CNTs a powerful field emission enhancer. However, in practice, like a flat panel display, the field emission enhancement of the entire field emission film cannot achieve the field emission enhancement of a single CNT. As a result, emission voltage of the whole system is increased, and current density is decreased. Meanwhile, the process technique becomes complicated, and the cost becomes relatively high.
What is needed, therefore, is a pixel tube for a field emission device that has good field emission efficiency and is easy to manufacture.